mz-adapter-guide

# Adapter Guide Skill When working on or reviewing the adapter layer or related crates, always read and follow the guidance in `doc/developer/guide-adapter.md`. That document contains correctness invariants, architectural notes, a list of optimizations that have been tried and rejected for correctness reasons, and a checklist for reviewing adapter changes. Read it before making changes and before reviewing them. Read `doc/developer/guide-adapter.md` now. When working on the timestamp oracle (`src/timestamp-oracle/`), also read the module-level docs in `src/timestamp-oracle/src/lib.rs` and `src/timestamp-oracle/src/batching_oracle.rs` for the `TimestampOracle` trait contract and the batching/linearizability invariants. When you or the user discover that an approach is incorrect or heading in a wrong direction, suggest distilling the learning into `doc/developer/guide-adapter.md`. Add it to whichever section fits best — a new correctness invariant, a new subsection under an existing invariant, a rejected optimization, or a new top-level section if needed. Describe what was tried, why it's wrong, and any relevant context. This keeps the guide up to date and prevents future re-discovery of the same pitfalls.